Double Factorial Prime

A double factorial prime is a prime number of the form , where  is a double factorial.

 is prime for , 4, 6, 8, 16, 26, 64, 82, 90, 118, 194, 214, 728, ... (OEIS A007749), the largest of which are summarized in the following table.

	digits	discoverer
	169,435	S. Fukai (Jun. 5, 2015)
	229,924	S. Fukai (Jun. 5, 2015)
	344,538	S. Fukai (Apr. 21, 2016)

 is prime for , 1, 2, 518, 33416, 37310, 52608, 123998, ... (OEIS A080778), the largest of which are summarized in the following table.

	digits	discoverer
	112,762	H. Jamke (Jan. 3, 2008)
	288,864	S. Fukai (Jun. 5, 2015)

REFERENCES:

Sloane, N. J. A. Sequences A007749 and A080778 in "The On-Line Encyclopedia of Integer Sequences."